During various surgical procedures, it is necessary to dissect bone or other tissue. Many conventional surgical instruments used for the dissection of bone or other tissue employ pneumatic or electrical motors to rotate a cutting element. In their most basic form, such surgical instruments typically include a motor having a rotary shaft, a dissection tool having a cutting or abrading element that is moved by the rotating shaft of the motor, and a coupling arrangement for connecting the dissection tool to the rotary shaft. The dissection tool often has a small shaft diameter in relation to its length. The shaft may bend or flail in use if not adequately supported or protected. The risk of bending is heightened when the shaft is used with a motor that is designed to reach speeds in excess of 72,000 rpm.
To support and/or protect a dissection-tool shaft, an attachment or tube may be provided that engages the motor and receives a portion of the dissection-tool shaft. Some attachments or tubes may remain stationary relative to the motor. An example of a stationary attachment is disclosed in detail in co-pending patent application Ser. No. 10/200,683, filed Jul. 22, 2002, the disclosure of which is incorporated by reference.
Other attachments or tubes may move axially or telescope relative to the motor, thereby allowing the surgeon to vary the distance that the distal end of the tube extends from the motor, and hence vary the distance that the distal end of the dissection-tool shaft extends from the distal end of the tube. Thus, the portion of the dissection-tool shaft received and supported and/or protected by the tube may be varied as desired or needed. For example, a decrease in the portion of the dissecting-tool shaft received by the tube may be required to accommodate spatial constraints associated with the surgical area. An example of a telescoping attachment is disclosed in detail in co-pending patent application Ser. No. 10/326,178, filed Dec. 20, 2002, the disclosure of which is incorporated by reference.
However, problems may arise during the operation of a surgical instrument having a typical attachment or tube. For example, the stiffness of the tube may not be sufficient to provide adequate stability to the cutting or abrading element, especially in light of the dissection-tool shaft being subjected to various static and/or dynamic loads during normal dissection operation. Also, due in part to vibration, any threadably engaged components of the attachment may disengage from each other during normal dissection operation.
In addition to the foregoing, for telescoping attachments, many configurations require one or more components to be added to the attachment to provide the telescoping functionality. These components may interfere with the surgeon's line of sight to the surgical area during the dissection operation. Also, it may be difficult for the surgeon to telescope the attachment in an incremental and repeatable manner.
Therefore, what is needed is a surgical attachment instrument that overcomes one or more of the above-described problems.
TABLE 1United States PatentPublicationapplicationPublication No.DateInventorSer. No.2002/0151902Feb. 17, 2002Riedel et al.10/102,7622002/0165549Nov. 7, 2002Owusu-Akyaw et al.10/135,6082003/0023256Jan. 30, 2003Estes et al.10/200,6832003/0163134Aug. 28, 2003Riedel et al.10/164,8672003/0229351Dec. 11, 2003Tidwell et al.10/164,8802004/0122460Jun. 24, 2004Shores et al.10/326,178
All patent publications listed in Table 1 are hereby incorporated by reference herein in their respective entireties. As those of ordinary skill in the art will appreciate readily upon reading the Summary of the Invention, Detailed Description of the Preferred Embodiments and Claims set forth below, many of the devices and methods disclosed in the patent publications of Table 1 may be modified advantageously by using the teachings of the present invention.